Right now, the only thing Sosa seems to be serving up is batting practice.

The right-hander was torched again yesterday, giving up an eighth-inning grand slam to Ronny Cedeno that turned a relatively tight game at Wrigley Field into an 8-1 Cubs laugher.

It was the second grand slam Sosa has allowed already this season and the second in just his past nine appearances. The Braves’ Kelly Johnson touched Sosa for a pinch-hit grand slam April 5 in an 11-5 Mets loss in Atlanta.

Sosa, who has served as a short reliever, long reliever and spot starter with the Mets, wasn’t immediately available yesterday after playing a role in each of the Mets’ two losses here.

Randolph seemed to be in denial when asked about Sosa after the latest setback, acting as if there was little reason to be concerned.

“That’s his job, doing different things for us,” Randolph said. “He can do short or long. You have to have a versatile guy, and he’s that guy for us.”

Versatile, maybe, but certainly not effective. Sosa no doubt was among the Mets most eager to get on the team charter out of Chicago after two miserable outings in a row here.

Sosa’s Windy City atrocity began Monday night, when he gave up a towering, three-run homer to Felix Pie in the eighth inning that blew open a close game and provided the final margin in a 7-1 Chicago win.

Sosa’s problem is a lack of velocity and movement on his fastball. He reached only 88 mph on the pitch he grooved to Cedeno for the grand slam yesterday, and the ball was straight down the middle with no sink.

Although Randolph insists he gives little credence to Grapefruit League numbers, Sosa’s current meltdown is surprising after how well he pitched in Port St. Lucie this spring. Sosa also was considered reliable in 42 appearances last season, a total that included 14 starts.

Now, however, the Mets are virtually conceding games every time they turn to Sosa. In short, Duaner Sanchez’s surgically repaired right shoulder can’t build up strength fast enough for Randolph and his bullpen.